Sound recording apparatus



1931 J. F. MELVIN, JR

SOUND RECORDING APPARATUS Filed Dec. 14. 1929 TJ JL.

gwvew/bm John I. Me lam, Jr. $3M bio 3 22603 Patented Dec. 1,1931 I: I i i i UNITED STATES PATENT*OFFICEf I I i .Iaoim F. ME IN, .13., or nEwYoRx, n. Y. 1 v

souin) maconnmo APPARATUS i imput tion filed December 14, 1929. Serial 1T0.- 41 ,010.

r Among the principal objects which the perpendicular relation to the slit 11 as can be present invention has in view are: to record seen bestin Figure 4 of the drawings. The sound waves photographically for reprodiaphragm 13 is preferably vibrated toward duction in coordination with kinetic photoand away'from the panel 10, and the slit 11. graphs of persons or things; and to produce It is obvious that as the diaphragm 13 moves 65 said records'noiselessly. toward the panel 10, the lighterarea delivered to and through the slit 11' and is diminished v in width. And it is equally obvious that as Figure 1 is aschematic View showing parts the diaphragm 13 is retracted or moved of the apparatus arranged as in service. away from the panel 10, the lighted area de 60 Figure 2 is an end view of the vibrating livered through the slit 11 is widened, or inmechanism employed in the present apparacreased lengthwise of the slit 11. Between. tusfl-s T I p the limits of the two extremes of the move liigure 3 is a longitudinal section of the ment is the whole gamut of modulation in same,th-e section'be'ing takenas on the line the sound produced.

8 -3in Figure 2. v I In the drawings, the source of light is inaFig'ure 4 is a face view of a housing for dicated as an electric lamp 14. This light is the photographic film on which the photoconveyed preferably through the open ended graphic record is made and the vibrating tubular core 15 with which the magnet 16 is diaphragm through which light is conveyed provided. The core 15 is suitably wound as to the film, the view being taken as from indicated, by the wire 17. The wire 17 'is the plane indicated by the line 44 in Fig.1. suitably connected with an electric source, the I Fig. his a detail view in cross section, and current taken therefrom serving to saturate on enlarged scale, of the vibrating diathe core to preserve and provide the contenphmgm d the mounting therefor; tion necessary to float the small finely wound coil 18 in the magnetic field between the pole a pieces 19 and 20 of the larger magnet. ln accordance with the present invention, The diaphragm 13 is normally suspended a photographic ribbon film 9 is employed. in concentric arrangement with the core 15 Drawings Description The film may be independent of what is by means of pins 21 and the supporting known as the master or picture film upon spring brackets 22. The brackets 22 are temwhich photographic negatives of the sound pered to provide sensitive springs adapted to producing object or person are being photosupport the diaphragm 13 in its neutral pographed. If the film is independent of the sition or normal position. The windings of said master film, then synchronizing means the coil 18 are connected by means of lead of any approved type is used for operating wires 23 with a suitable source of electric enthe two films simultaneously. ergy, preferably what is known as the alter- The said master film is not herein described nating current, of desired voltage. This curor claimed. The film 9 is covered by the rent is subject to modulating influences. panel 10 and is otherwise protected from the These influences are acoustically produced light except where the same enters through through any suitable medium.

the elongated and narrow passage or slit 11, As the tension in the small coil 18 is inpast which the said film isbeing rapidly creased and diminished, the magnetic action moved. The slit 11 is formed in the panel between it'andthe magnet 16 is varied.

10 in a position transverse the length of the If now the current tension in the wires 23 film 9 and transverse the direction in which be varied or modulated by a suitable mechsaid film is moved. anism that can be influenced by sound waves,

Light is conveyed to the film through the the tension in the coil 18 will be correspondsaid slit 11 and a slit 12 formed in the vibratingly influenced and the diaphragm 13 will 0 ing diaphragm 13. The slit 12 is disposed in be moved to and from the panel 10, with the result that the light area delivered through the slit 11 is varied in direct proportion as the diaphragm is approached or receded to and from the panel 10.

When, now, the film 9 is developed, alight path is produced, the width of which is mo mentarily varied. WVhen this film is now passedrbetween, a light source andv a photosensitive electrocell of approved type, said cell having incorporated therewith, means for varying the sending current of a radio 7 transmitting unit embodying asoundproducing mechanism, a reproduction of the sound which was instrumental informing the said path, is repeated in the speaker; ..When.desired, lenses such as indicated by v the numeral 24 may be employed effectively for concentrating.oriintensifying as the case maybe, the light transmitted from the elementl l. f

; NVhile there has' beenrh'erein described means for varying the width of the lightpath, said means'employing a passage of a given height and avibrating obscurating; dia; phragm havin a corresponding or cooperating slit or narrow passage,th'e movement of which, to and from the first named passage, varies the width of the light path, I may pro du e-the same result or the close equivalent thereof by employing amirror or reflector arranged to direct the pencilof light through Said passage, said ray operating from the edgeot the film as a base orneutral line in the manne and as now produced. But in accordance with the present invention, the

. luminating element, said obscurating'memher having an elongated light passage therein-alligned with said slit for varying the width of the light ray, reaching said film through said-slit, and electro-active means for reciprocating said obscurating -member to and from said covering member in come spondence with the electro impulses received by said electro-active means.

2. A sound, recording apparatus compris- 3 ing means for moving a photo-sensitive film at a fixed rate of speed, a covering'member stationarily disposed in juxtaposed relation to said film, said coveringmember having an elongated narrow slit extendingtrainsverse thepath of movementof said film, a

stationary illuminating element for deliver ing light through said slit, a movable obscurating member reciprocatively dlsposed between said covering member and said illuminating element, said obscurating member having an elongated light passage therein aligned with said slit for varying the width of the light ray reaching said film through said slit, and electro active means for operating said obscurating member in correspondenc'e'with electro impulses received thereby, said means embodying an electro-magnet having'a tubular core disposed in line with and between said/illuminating element and said passage in saidobsc'urating member.

3. A sound recording apparatus comprising means for moving a photo-sensitive film ata fixed rate of speed, a covering member stationarily disposediin juxtaposed relation to saidfilm, said covering member having an elongated narrow slit extending transverse the path of movement of said film, a stationary illuminating element "for delivering light through said slit, a movable obscuratmg member reciprocatively disposed between said covering member and said illuminating element, said obscurating member having an elongated light passage therein aligned with said slit for varying the width of the light ray reaching said film through said slit, and eleetro-active means for operating said obscurating member in correspondence with the electro impulses received thereby, said means embodying an electro-magnet having a tubular open core-interposed. between said illu minating member and said obscurating element,'an'd elect-ro-active means supporting said obsourating member to float between the fields of saidlelectro-magnet, said magnet bein adapted to receive-a continuous electric current arranged to, be modulated by a suitable sound transmission apparatus.

JOHN F. MELVIN, JR. 

